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Power outside normal levels?

Hi Guys,

 

I have been with virgin for a few months, and have been having issues off and on with the modem rebooting and /or dropping internet and i suspect it could be down to a cabling issue, as the power values seem very high.

 

Any chance someone can have a look and confirm and i will then call for support.


Thanks in advance

Downstream tab details

Channel Frequency (Hz) Power (dBmV) SNR (dB) Modulation Channel ID
1 266750000 3 38 256 qam 17
2 138750000 1.7 37 256 qam 1
3 146750000 0 37 256 qam 2
4 154750000 2.2 38 256 qam 3
5 162750000 1.5 38 256 qam 4
6 170750000 1.2 38 256 qam 5
7 178750000 1.7 38 256 qam 6
8 186750000 1.5 38 256 qam 7
9 194750000 2.2 38 256 qam 8
10 202750000 1.7 38 256 qam 9
11 210750000 1.5 38 256 qam 10
12 218750000 3.5 38 256 qam 11
13 226750000 4 38 256 qam 12
14 234750000 2.4 38 256 qam 13
15 242750000 3.4 38 256 qam 14
16 250750000 5.5 40 256 qam 15
17 258750000 3.4 38 256 qam 16
18 274750000 5.9 38 256 qam 18
19 282750000 6 38 256 qam 19
20 290750000 3.5 38 256 qam 20
21 298750000 4.4 38 256 qam 21
22 306750000 6.8 40 256 qam 22
23 314750000 5 38 256 qam 23
24 322750000 3.5 38 256 qam 24

 

Downstream bonded channels
Channel Locked Status RxMER (dB) Pre RS Errors Post RS Errors
1 Locked 38.9 1280 0
2 Locked 37.6 11787 40
3 Locked 37.3 23354 0
4 Locked 38.6 1582 0
5 Locked 38.6 3846 0
6 Locked 38.6 4673 0
7 Locked 38.9 2617 0
8 Locked 38.9 3466 0
9 Locked 38.9 1508 0
10 Locked 38.6 2671 0
11 Locked 38.9 3952 0
12 Locked 38.6 558 0
13 Locked 38.9 313 0
14 Locked 38.6 1810 0
15 Locked 38.9 562 0
16 Locked 40.3 31 0
17 Locked 38.9 712 0
18 Locked 38.6 111 0
19 Locked 38.9 93 0
20 Locked 38.6 1056 0
21 Locked 38.6 798 0
22 Locked 40.3 287 0
23 Locked 38.6 605 0
24 Locked 38.6 1198 0


Upstream tab details

 

Channel Frequency (Hz) Power (dBmV) Symbol Rate (ksps) Modulation Channel ID
1 53700036 5.7 5120 64 qam 13

 

Upstream bonded channels
Channel Channel Type T1 Timeouts T2 Timeouts T3 Timeouts T4 Timeouts
1 ATDMA 0 0 0 0


Network log tab

 

10/12/2019 13:55:8 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 13:55:13 Warning! Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 13:55:17 critical Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:05:44 critical Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:05:44 Error TCS Fail on all Upstream Channels;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:05:44 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:07:0 critical Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:07:0 Error TCS Fail on all Upstream Channels;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:07:0 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:08:8 critical Unicast Ranging Received Abort Response - initializing MAC;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:08:8 Error TCS Fail on all Upstream Channels;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:08:9 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:08:48 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:08:51 Warning! Lost MDD Timeout;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:09:17 critical Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
10/12/2019 14:13:37 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
15/12/2019 09:37:42 Error DHCP RENEW sent - No response for IPv4;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/12/2019 17:06:11 Error DHCP REBIND WARNING - Field invalid in response;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/12/2019 17:06:11 notice DHCP Renew - lease parameters tftp file-cmreg-vmdg505-rtsxxl35016u+voc-b.cm modified;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;
16/12/2019 21:43:31 critical No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

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Re: Power outside normal levels?

downstream is ok - some possible noise but hub is coping with that - upstream is far too high - read 57 for 5.7 - its a bug in firmware and there is only one upstream - there should be 4 - max limit is about 50

check all the coax connections are tight - do a full reset and if nothing changes post back and wait for VM to get to the thread and book a tech

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Re: Power outside normal levels?

Hi Tony,


Thanks for the quick reply. To expand on the situation, a few weeks after getting Virgin line installed, there was very heavy rain, which I suspect caused issues with my line. 

I raised a support call, and a tech was sent out, who swapped out the modem since then I have had the issues.

I only have the broadband installed, no tv(and the phone goes through the hub these days), and the cable is very tight and only short between the hub and the cable outlet socket on the wall. Also done a full reset recently(used to run the hub in modem mode with the same results)

Also, the upload should be circa 35mb(i am on the 350 down) but only get early / mid 20's.

Here is a link to the speedtest.net results. https://www.speedtest.net/result/8863629317

Thanks again bud

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Re: Power outside normal levels?

swapping the hub can be their way of doing something - leaves you with the thought that it will be solved

as i say the upstream is a mess - you need a tech who will [really] do something

will flag the thread

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Re: Power outside normal levels?

Thank you Tony, gratefully appreciated bud
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Re: Power outside normal levels?

Hi chqshaitan, 

 

Thanks for your post and welcome to our community 🙂

 

I've checked the hub and there's definitely an issue with the upstream.

 

I've popped you over a private message so I can arrange a technician for you.

 

Alex_Rm

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Re: Power outside normal levels?

Keep an eye on the downstream power levels, and ask the technician if they can be improved, because the range of power levels looks far too wide to my eyes, from 0 dBmV on channel 3, to 6.8 dBmV on channel 22. 

You can see a correlation across the channels between lower power levels and higher error rates, although it is important to realise the range is more important in possibly causing issues here than the absolute levels.  General view is that having power levels tightly clustered at low single digit or 0 dBmV values is optimal. I'd be very surprised if the downstream levels your hub is subject to are anywhere near compliant with the makers's guidance, although I'm sure that -tony- is right that your biggest problem is the upstream.

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Re: Power outside normal levels?


@chqshaitan wrote:

To expand on the situation, a few weeks after getting Virgin line installed, there was very heavy rain, which I suspect caused issues with my line. 

The downstream power goes up and down. If you plot it, you will see "standing waves". That can be a tell of water ingress.

 

 

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